UmneyDurak

Hi.

Anyone who tried both, can you give cons/pro of Quarq compared to SRM? Is the reliability/accuracy there now? Also is it possible to display, time, cadence, HR, speed, power, all on the same screen?

I have Dura Ace SRM now that is 7 years old now, and I was contemplating on switching to Quark, or maybe getting the latest one used. My biggest gripe against SRM is that it's not really self serviceable. You need to send it in to replace battery. I mean sure you can try to get aftermarket battery yourself and solder that in, but capacity is lower and you need to be handy with a soldering iron. I also like the SRM software, and aforementioned ability to see time, cadence, HR, power, speed all on one display.

Thanks.

Derby

Can't help on the comparison between SRM and Quarq but you can definitely get the display needs met with a Quarq + Garmin 500. You can have up to 8 parameters, including those you specify, per screen. Quarq will provide the Cadence + Power without the need for a cadence sensor. I think the accuracy between the SRM and Quarq are pretty close these days. Reliability for my Quarq (1st gen) has been stellar so far.

Racer Ex 

Find someone with a 7 year old Quark that still works.

I'd stick with what you have or upgrade to another SRM.

Data sample rate on the Garmin is much lower than the SRM BTW.

brian416

I have an SRM (wireless Specialized) and Quarq (S975). They both have stable zero offsets and if there is any difference in power between them, I certainly can't tell.

Battery: SRM requires soldering in a new battery every 3-400hours, with the Quarq, you unscrew a cap and pop a new battery in, 10 second job.

Waking crank up: My SRM requires spinning the cranks forward to wake them up, with the Quarq, I can spin them backwards and they wake right up. It seems pretty minor but it is so much easier to zero the Quarq at the start of the ride than my SRM.

Zeroing while riding: My Garmin 800 autozeros with my SRM, it's always dead on and means you really don't have to zero them after you start riding. The Quarq requires backpedaling 4-5 times to zero while riding.

If I were to purchase another powermeter, it would most likely be a Quarq.

UmneyDurak

What is the rate on Garmin? Can you elaborate on your recommendation about staying with SRM or upgrading?

Hmm, which one do you have? I have an old wired one with PCV, and I can wake it up by spinning backwards. Yeah one of the things I don't like about SRM you either have to send it in, or solder new battery in. Which is what I done last time, but battery capacity is lower (not to mention my soldering skillz are lacking lol).

echappist

sample rate on Garmin: 1Hz

sample rate on SRM PC: 2Hz

-----

do a search, SRM vs quarq issue has come up quite a bit. Quarq has been known for less than ideal offset drift in wet conditions.

Racer Ex 

The new wireless SRM's get some pretty stout battery life...800-1200 hours.

Garmin samples 1:3 compared to the PC7, according to what I've read.

Failure rate on the old Quarks was around 80% or more. Most folks have had to send at least one back, I know of one case where it's been 4. And having talked with several coaches they have a lot of accuracy issues, that's certainly been my experience. The latest edition hasn't been out long enough to erase that record, and came delivered with firmware issues. Bad sign.

Not a huge issue in Norcal but Quarks sometimes drown in the rain and I've seen SRM's submerged with no issues. Much more stout weatherproofing.

ProTour teams buy SRM's. There's a reason for that.

You've had your SRM for 7 years, my guess is other than the wired pickups it's been plugging along with the occasional battery change. If you can't solder buy a battery and run it down to a local electronics repair place with a six pack of microbrew. I know of wired units that are 15 years old and are still chugging. Ammortize out the cost, compare the downtime and accuracy issues, check out if you can get a Dura Ace Quark, and then look at long term resale if you think you might flip it.

Both have great customer service, you just won't need SRM's for much other than a battery if you want them to do it. And you might want to hold off a bit because SRM is working on a rechargeable unit; it's appeared on some of the ProTour bikes.

brian416

They updated the wireless cranks so that they no longer turn on by spinning backwards, not sure why though.

I have a PCVI and 800. The PCVI can record at .5 second intervals and the Garmin at 1 second. I've run them side by side with 1 second recording and get the exact same power numbers. With a Garmin you can include average power for the lap on the same screen. It's this feature that causes my PCVI to sit on a shelf and only get used when I'm calibrating the cranks.

rbart4506

I find the offset drift problems on the Quarq to be worse in the wet when it is cold... Wet and warm weather seems to be ok...

tetonrider

Battery life on most SRM units in the current line-up is 1,700 hours of use. That is more than 3 years for most riders. Some units have lower capacity due to the available space in the spider (e.g., 2x10 MTB units).

While I generally prefer user replaceable items where all else is equal, if one has no soldering skills, sending the crank in to SRM once every 3-5 years where they will check it over thoroughly while they have it is probably not a bad thing.

tetonrider

Just curious, but why do you find that this is so important? Average power is one button press away on the SRm head units. I was the guy with 10 data fields on each screen of my garmin (does anyone find that surprising? ) so was understandably nervous when making the switch away from garmin.

i soon realized why real-time AP doesn't matter: if my goal is an interval at 300 watts, all that matters is what I am doing right now. If I have made it halfway through and my AP is 280w, that doesn't mean that I Gould do the remainder at 320. Took me a long time to figure that out, as I had some years where I was aiming for AP goals.

The found of SRM has a strong belief on this matter, so the unit reflects his sensibility. After training this way for a number of years I am inclined to agree.

Alaska Mike

I've submerged my Quarq S975 completely- as in, I was riding along a bike path, went into an underpass, and found it was flooded. I stayed up and rode it out (slowly) to the other side, but I was reading my Edge 500 under a couple inches of water. Every sealed bearing on the bike was trashed, but the Quarq was fine and hasn't missed a tick in the 9 months since. Maybe I just got lucky with mine, but my RIKEN hasn't given me any issues either.

Racer Ex 

It would seem so.

I'd hit the battery O-ring with silicone grease regardless. Standard practice for divers.

echappist

that's one button press too many. And given the variability of terrain, what i'm doing right now may very well be 20 watts higher or lower than the target. This is almost the same as saying: well, my speedometer said i was riding 21mph most of the time i looked down, so i think i was averaging 21mph during the whole thing.

Now of course, maybe you and Uli don't need it, but i find it tremendously helpful. Hell, i have three fields displayed for my workout: lap avg, 10 sec rolling, and 3 sec rolling. Why? Because i can, and because i get better pacing from my intervals, especially the shorter ones(1-2 minute variety).

Now you can try to argue against the utility of that, but just so you know, this was my bike set up from a few years back. I'll let you guess why i did it.

UmneyDurak

Anyway...Are the new SRM that much better then old ones? Wireless is nice, and with ANT you can use other head unites, but I am fine with SRM one. Is there anything else? I am starting to have second thoughts about whole thing. lol My current one works, and SRM seems to still support it in terms of service.

tetonrider

well, it is just a point of view, but I will respond because the speed analogy is not the same thing I was saying.

Similar to y, I ad lap avg, 3s and 30s averages on my interval screen for my garmin. For what it is worth, my SRM is set up to show power smoothed over the last 3 revs, but as y probably know that is configurable.

Im going to assume you are doing paced intervals vs all out at every pedal stroke. Consider this: let's say you are doing 5' efforts at 400w, pretty realistic for your size. If you look down 1' in and see that've been doing 420 for that minute, how will you respond? Should you then aim for 395 for the next 4 minutes? If you realized you were riding at 380 (inadvertently or it was all you could do in that minute), would you then try to ride 405 for 4'?

My point is that if your target is 400' the goal is to do 400 for every stroke. You missed a stroke? Well, that one is gone so don't worry about it and carry on with the next one.

Again, just a point of view, but I offer it because I thought all the data on the screen at the same time was ESSENTIAL until coming to the above conclusion. I believe it has made my riding and the quality of my intervals better. It may not work with you, but it is something to consider, and the worst thing is that taking a fw moments to really think about it has no downside. In fact, it may just reinforce that you are making the right call for you. Never hurts for me to reexamine my long-held beliefs.

I can get to my interval's average power easily (the SRM buttons are easier to work with than the garmin 500's awkward side buttons (and I still use a garmin), so I don't think it is a downside. Again that is my opinion.

Now if one is continually onto ring the screen every few seconds of an interval, I can see more value in having that stuff displayed, but personally I cannot stare at the screen or it has a tendency to make time stop. I am pretty good at pacing by feel and as terrain shifts I still just have the same goal.

Well, the only conclusion I can draw is that it appears to be a race and not a training session, so it is different than the above examples you used regarding terrain affecting your pacing of intervals. For a race, I try to do things that will help me win and assume others are the same. Did this get you any wins when riding the setup? I will bet that no one has won or lost a race due to the presence or absence of AP on a screen, as long as they had a slightly smoothed version of current power.

IMHO, YMMV, etc.

tetonrider

Power is power. New ones have better battery life (takes away the most significant negative in my opinion) and fewer wires. We can debate the merits of that. I like wireless but a wired setup has some perks.

Srm will support you for a long time an when they cannot they will often offer an incredible dal on a current unit.

if you are happy now, there is not much *need* to switch. *wanting* to switch is another matter.

dnuzzomueller

Now I know I am going to receive some type of bashing for this but isn't there a point where the average power over a period is "Good enough" for the length/ type of the interval that you are doing?

For example if you are doing a sprint workout you would want every single stroke of your 15 seconds to be in Z7. But lets say you are going out and doing a 4 X 15 Z4 workout. At that point would it matter less the exact power you were putting out at any given point?

It just seems like the further and further you push the time of the interval the more it "smoothes out" your power. I mean according to Coggan your 1 hour NP is theoretically your FTP and for all anyone knows that NP could have been produced when doing a crit with an insane number of surges.


I guess I should boil this down into a question relating to my own Quarq in any case: I get heckled by teammates/ friends who all swear by 3 second power and 3 second power only for their intervals. I personally prefer 10 second for my longer stuff but if each of those pedal strokes really matter then shouldn't we all be using no averaging whatsoever?

Grumpy McTrumpy

I have and use both. The Quarq works fine for a lot less money.

I did have to send it back to Spearfish when it was new however as it was not working properly. It has been reasonably good for the past two years though.

The SRM is slightly better in terms of spikes and spurious readings, but the difference isn't much.

I also have old SRMs. One of them was even old enough that it needed to be replaced due to microfractures. They gave me a good deal on a new wireless spider.

I also have old and new powertaps.

Everything eventually wears out. The Law of Impermanence. I'd go with whatever your gut tells you and don't expect it to last forever.

waterrockets 

I'll start off by saying that if I ever get out of the PowerTap club into the spider club, right now I favor SRM by a pretty big margin. The upgrade is not in my plans though, as the PowerTaps are working great for me, and I don't swap wheels based on activity (racing, TT, training, etc.).

Interval power is important to the way I train. I run 10s averaging, and hold target power throughout, unless I realize the target power is incorrect due to changes in fitness or fatigue. When I change my target mid-interval, it's an explicit change, and the number I get is important to me.

I'm still running Cervos on my bikes, so I only get to choose one duration, but I agree with your reasoning.

If I'm riding with interval avg on the display, I glance at it ever 15 seconds or so and would never accidentally end up 20W over unless I changed my target, or have some variability in my plan. On my hill repeat course, I come out of the first minute about 30W over because it starts off at 15% grade and I find it suits me better to ride that course a bit more intense on the steeps, as it would be in a race.

That said, if I did suddenly discover that I was accidentally 20W over my target, and then decided I wanted to correct it, I would do so by following the average on my display. You let up just a touch, and you'll start dropping a Watt every 15 seconds or so. I'll use this technique and end up meeting my target at the end of the interval.

I can consistently run ZCI™s and hill repeats with power averages met to the exact Watt on my display.

Yep, I offer the above not as a recommendation, but as an example of how I like to pace.

It will indeed smooth out over time, but if there is a greater inaccuracy in a given system, how do you know that the inaccuracy trends to stay centered, rather than favoring high or low readings?

Changing to no averaging on power is going to be more stochastic, but not because your legs are putting out inaccurate amounts of force or something. We average our power because our brains can't process instantaneous numbers in a 20W range to determine what the average of those numbers is. You would tend to favor the 100s and 10s place digits, and could be missing the big picture. All power meters have error, and that will be stochastic as well, but it's an error, and averaging will not correct it (you can't pull the correct numbers out of thin air).

tetonrider

sure!zones are also just that--zones (ranges). People want to pin their threshold, for example, to a number, but on any day what we can do at "100%" is still a range. AP is even less important in that circumstance.

That aside, if someone wants to have an AP target for some sort of steady state effort, the way to get there is to have every pedal stroke as close to the desired average as possible and generally not to make up for dips in power or to ease off a bit to counteract spikes. Mathematically AP is best hit by constantly making up for the prior pedal strokes, but a point of view is that it is not best for the training. Again, just a point of view and something to consider.






people use many ways to estimate threshold, and their is an inclination to pick the highest one. Some crits (or efforts) have a tendency to produce high power files....eg something like the mt hood crit where one must surge up a hill then basically coast due to the nature of the course/turns. This will suit someone with more anaerobic capacity and will likely overestimate what could be done for a steady-state hour. Just something to think about when using NP for these things.

3s is basically instant power with just a hint of smoothing to calm down the display so our eyes/brains can process it. 10s obviously has more smoothing applied. Use whatever works for you and gives you the most success!

AzTallRider

I agree wholeheartedly with "targeting your target" with each stroke, and that's how I do my intervals. That, however, doesn't diminish the value of having an average for the lap displayed. I use it to see how well I'm keeping to my target for an interval, and when I'm not targeting a specific power, to see what I'm averaging. What I'm averaging going up one of our local benchmark climbs is of interest to me. It's a good indication of my form, and whether I should be able to push harder than I am without blowing up. Stuff like that. IMO, it's also of value for TT efforts. If I'm targeting 280, but averaging 260, that's good to know. Similarly, if I'm doing a training crit with a goal of minimizing my power, it's nice to know what I'm averaging, real time, in addition to looking at it later on. PM's are about information, and we each have our way of looking at it. Not offering a display because you don't agree with how it might be used is just silly.

That said, so far my SRM kicks the ass of the Quarq (4 different units) it replaced. I just forget about it, while the Quarq was always something to contend with.

tetonrider

You probably know this, but not everyone in this thread may know it: the SRM head unit allows the user to choose whether there is any smoothing applied to the power read-out. i like smoothing over 3 revolutions, but one could choose smoothing over 10, 15, or 60 strokes (or anywhere in between). This won't be a differentiator between Garmin and SRM head units.


i appreciate various pacing strategies. i also appreciate that someone who is careful should not suddenly wind up way off in terms of power on the 1st minute of their interval (however they choose to monitor it).

All just good food for thought. As stated in an earlier post, I was shocked to find out how much I didn't miss AP on my main screen as someone who felt he was reliant upon it.

Of course, more choice for the user is better, and I will be somewhat surprised if the pc8 comes out and does not have some more control over what fields are displayed. The market is sort of demanding it, and allowing a user to turn AP on or off on one screen is a good thing.

At least we're not talking about how necessary real-time NP and IF are!

MDcatV

wow. i am like a right brained guy training with power. maybe that's why i'm not as good at this sport as most of you all.

OP - I have a quarq riken and a SRM. I started training with power in late 2007 with a power tap and before that borrowed some power taps to give them a try (they sucked hard - didnt work in the wind, rain, humidity, cold, warm, shade, whatever). With limited wheel choice, I gave up the ptap in winter 2009 and switched to a quarq because a buddy of mine was a dealer and I could get one for about half the price of an SRM.

The quarq worked fine as far as I could tell, but again, considering my right brained tendencies toward training there could have been drift or offset inaccuracies that I wasnt likely to detect. In May of this year, so about 4.5 years later, the quarq started telling me i was doing 3,569 watts for over 5 minutes. I thought wow, I've improved, but after rigorous statistical analysis realized it was a strain gauge issue. Quarq sent me a Riken (no cost) to replace my wonky cinquo, and due to a gxp bb already being in place, I slapped it back on and it works fine. Although my stupid magnet keeps falling off, which is pissing me off.

In the mean time, because I'm doing my best to keep the secondary markt economy moving, and I wanted a pmeter for my TT bike, I bought a used SRM on a DA 7800. I'm hoping to get it assembled this week, and hope i can figger out how to make the fecking magnet stay on.

I'll use a garmin edge 500 for both because I know which buttons to push to get the readouts I want, didnt want to drop another $X for the SRM PC whatever it's called, and didnt want to put another goddam magnet on my bike to get a speed readout on the SRM PC whatever it's called unit.

In the end, I dont think you can go wrong, they're both good pieces of equipment that I think will provide you with the information necessary to implement a successful training program.

echappist

aww, you are too kind . Maybe for 4 minutes, def not 5.

you probably know the type i am: someone who looks at the damn thing every 20 seconds while doing a hard interval. i'm like a Skybot, except i don't dope and can't climb.
that's not the point as i don't have photos of my bike from 2011 in training mode. In training, i was probably pressing the damn scroll button once every minute when i had only one display unit.

THat said, in racing, i agree it doesn't matter as 15 second rolling average is sufficient for work in a break, and the only time lap avg matters is when you are soloing. A lot of times these days i don't even bother to hit the lap button when something goes (when i initiate a break or try to bridge across to one).